High thermal conductivity insulating resin composition, high thermal conductivity insulating film, and method for manufacturing the same

Abstract

The present invention relates to the field of thermally conductive materials, and more specifically to a high thermally conductive insulating resin composition, a high thermally conductive insulating film, and a method for producing the same. The high thermally conductive insulating resin composition comprises 40 to 80 parts by weight of epoxy resin and 20 to 60 parts by weight of thermally conductive filler, wherein the thermally conductive filler includes a composite material of plate-like corundum and cubic boron nitride, cubic boron arsenide, and sheet-like hexagonal boron nitride. The high thermally conductive insulating resin composition submitted by the present invention constructs a complete thermal conduction network using sheet-like and spherical particulate thermally conductive fillers with different particle sizes, and the designed epoxy resin-thermally conductive filler system exhibits a high thermal conductivity coefficient, high thermal conductivity and good insulation, while simultaneously overcoming the drawbacks of conventional thermally conductive films, such as low mechanical properties and heat resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of thermally conductive materials, and specifically, to a high thermally conductive insulating resin composition, a high thermally conductive insulating film, and a manufacturing method thereof.

Background Art

[0002] In recent years, the integration and assembly technologies of microelectronics have developed rapidly, and electronic devices and components are becoming increasingly miniaturized and multifunctional. Their operating frequencies are increasing rapidly, the heat generated during operation is rapidly accumulating, and the environmental temperature is continuously rising. If the accumulated heat is not timely diffused to the outside, it will have a great impact on the use reliability of the devices and components and shorten the service life. Therefore, in order to ensure that the devices and components can operate smoothly and efficiently, how to release heat in a timely manner has become an issue to be solved in the field of microelectronics implementation. Currently, in order to ensure the normal operation of devices and apparatuses, generally, it is necessary to use a thermally conductive material having high thermal conductivity to release heat in a timely manner. Among them, polymer-based thermally conductive composite materials are most widely used because of their excellent processability and relatively low cost.

[0003] Epoxy resin has become the most widely used polymer matrix because of a series of advantages such as its excellent electrical insulation, thermal properties and mechanical properties, as well as a simple molding process, low viscosity, and small curing molding shrinkage rate. However, since the thermal conductivity of epoxy resin is relatively low (0.18 W / m·K), usually, it is necessary to add a thermally conductive filler to improve the thermal conductivity of the composite material. There are mainly two ways to improve the thermal conductivity of the thermally conductive film: 1) adjusting the molecular structure of the epoxy resin polymer material itself to reduce defects such as the mismatch of molecular vibration and lattice vibration, achieving high crystallinity or orientation, and finally achieving the purpose of reducing phonon scattering; 2) filling the epoxy resin with high thermally conductive particles such as boron nitride, silicon nitride, and aluminum nitride. The most commonly used filler is boron nitride.

[0004] Chinese patent publication number CN109280332A discloses a boron nitride / epoxy resin thermally conductive insulating composite material. The patent application describes modifying and altering the surface of boron nitride using a silane coupling agent, and further filling an epoxy resin with the modified sheet-like hexagonal boron nitride powder and cubic boron nitride powder in a certain ratio. The thermal conductivity of the resulting composite material is improved to some extent, but there is still a problem that the improvement in thermal conductivity is relatively small.

[0005] To further improve the thermal conductivity of composite materials, Chinese patent publication number CN111500019A discloses a high thermal conductivity insulating epoxy resin material based on BN-Al2O3 modification and a method for producing the same. By modifying the surface of BN-Al2O3 and grafting epoxy groups, BN-Al2O3 is bonded to the molecular chains of the epoxy resin, improving the compatibility and dispersibility between nano-Al2O3 and BN and the epoxy resin, and giving the epoxy resin excellent insulation and thermal conductivity. However, if excessive organic reagents are introduced, it can cause contamination of the chemical reagents during surface modification, reducing environmental considerations. Furthermore, the thermal conductivity of the composite material after modification is only 0.542~0.815 W / mK. [Overview of the Initiative]

[0006] The present invention overcomes the drawback of conventional thermal conductive filler-epoxy resin systems mainly composed of boron nitride, which have relatively low thermal conductivity due to incomplete construction of the thermal conduction network, and also overcomes the drawbacks of conventional thermal conductive films, which have low mechanical properties and heat resistance. To achieve this, the present invention provides a high thermal conductivity insulating resin composition, a high thermal conductivity insulating film, and a method for manufacturing the same.

[0007] To achieve the above objective, the present invention provides the following technical solutions.

[0008] A highly thermally conductive insulating resin composition comprising 40 to 80 parts by weight of epoxy resin and 20 to 60 parts by weight of thermally conductive filler, wherein the thermally conductive filler includes a composite material of plate-like corundum and cubic boron nitride, cubic boron arsenide, and sheet-like hexagonal boron nitride.

[0009] The inventors of this application construct a thermal conductive system by selecting fillers of different forms and thermal conductivity, where plate-like corundum has a spherical particle structure, cubic boron nitride has a nanosheet structure, cubic boron arsenide has a spherical particle structure, and hexagonal boron nitride has a scale-like structure. By employing a means of mixing spherical particles and sheet-like materials, the sheet-like thermal conductive fillers are oriented along the horizontal direction to construct horizontal heat conduction pathways, while the spherical particles fill the gaps in the thermal conductive fillers, improving the horizontal heat conduction network and simultaneously acting as bridges, thereby constructing vertical heat conduction pathways. This improves the thermal conductive system constructed in both the horizontal and vertical directions.

[0010] Furthermore, while cubic boron nitride has the advantage of a high thermal conductivity and stable heat transfer as the most commonly used thermal conductive filler, its relatively high brittleness makes it prone to cracking and fracture during use, affecting the stability and durability of the thermal conductive system. Therefore, this problem with cubic boron nitride can be solved by compounding it with plate-like corundum. In addition, by pre-compounding plate-like corundum and cubic boron nitride, the sheet-like and spherical particles within it are integrated, reducing the interfacial impedance between different thermal conductive materials. This also achieves a uniform distribution of plate-like corundum and cubic boron nitride in the thermal conductive system, resulting in a three-dimensionally dispersed distribution of the thermal conductive system. This avoids localized concentration phenomena such as overlapping of sheet-like particles and adhesion between particles, and at the same time, it is useful for constructing a variety of thermal conductive systems and is advantageous for improving the dispersion and stability of thermal conductive materials.

[0011] In this way, by uniformly distributing plate-like corundum, its high compressive strength, high toughness, and high crack resistance properties uniformly increase the compressive and crack resistance of the entire thermal conductivity system, making collapse less likely to occur at specific locations.

[0012] Furthermore, the ratio of thermally conductive filler to epoxy resin is based on the fact that the thermally conductive filler is uniformly encapsulated in the epoxy resin through compounding. While the addition of thermally conductive filler can improve the thermal conductivity of the composition, if too much thermally conductive filler is used, the small amount of epoxy resin cannot uniformly encapsulate the thermally conductive filler, making it impossible to form a uniform composition. Therefore, by controlling the ratio of the two to 40-80 parts epoxy resin and 20-60 parts thermally conductive filler, a composition with excellent thermal conductivity and uniformity can be obtained.

[0013] In summary, by selecting various thermally conductive fillers of different forms and fusing the sheet-like and spherical particles within them, a uniform thermally conductive system with diverse structures and thermal conduction paths in both horizontal and vertical directions can be constructed, significantly improving the thermal conductivity of the composition. At the same time, the mechanical properties of the manufactured composition are significantly improved due to the presence of the plate-like corundum.

[0014] Preferably, the average particle size of the plate-like corundum is 1 to 3 μm, the average particle size of the cubic boron nitride is 100 to 400 nm, the average particle size of the cubic boron arsenide is 100 to 300 nm, and the average particle size of the sheet-like hexagonal boron nitride is 5 to 15 μm.

[0015] More preferably, the average particle size of the plate-like corundum is 1 to 3 μm, the average particle size of the cubic boron nitride is 200 to 400 nm, the average particle size of the cubic boron arsenide is 150 to 300 nm, and the average particle size of the sheet-like hexagonal boron nitride is 5 to 15 μm.

[0016] More preferably, the average particle size of the plate-like corundum is 2 μm, the average particle size of the cubic boron nitride is 300-350 nm, the average particle size of the cubic boron arsenide is 200-300 nm, and the average particle size of the hexagonal boron nitride is 10-15 μm.

[0017] Because the particle size of the scaly hexagonal boron nitride sheet is close to the thickness of the film after the composition has been cured into a film, it plays a role in penetrating the film and can significantly improve the thermal conductivity of the thermally conductive film. Cubic boron nitride and cubic boron arsenide with relatively small particle sizes can fill the gaps in the system to the maximum extent at their respective particle sizes, reduce the interfacial thermal resistance between the resin and the powder, and thereby improve the thermal conductivity.

[0018] Here, the molecular particle sizes of cubic boron nitride and cubic boron arsenide are both nanoscale, while the molecular particle sizes of plate-like corundum and sheet-like hexagonal boron nitride are both microscale. By combining nanoscale and microscale particles, a multilayer three-dimensional structure can be constructed. Nanoscale particles are advantageous for improving the surface activity and reactivity of the material, while microscale particles have a larger surface area. Such a multilayer structure is advantageous for improving the thermal conductivity coefficient of the thermal conductive system. Furthermore, after co-mixing thermal conductive fillers with different particle sizes, the advantages of each can be realized, utilizing the large specific surface area and reactive activity of nanoscale particles, as well as the high mechanical strength of microscale particles. The large specific surface area and reactive activity help improve the interaction between the thermal conductive system and the epoxy resin, increasing the contact area with the epoxy resin, while the high mechanical strength can improve the structural stability of the thermal conductive system. The synergistic effect of both improves the overall thermal conductivity of the resin composition.

[0019] Furthermore, in order to meet the plate-like corundum particle size requirements for the film manufacturing process of the present invention, it is necessary to purchase commercially available finished products and perform microprocessing to obtain small particles with an average particle size of 1 to 3 μm. If larger particles are used, film formation becomes difficult and the flatness of the manufactured film is reduced.

[0020] Preferably, the composite material of plate-like corundum and cubic boron nitride is obtained by compounding plate-like corundum having a relatively large grain size as the core and cubic boron nitride having a relatively small grain size as the shell.

[0021] Plate-shaped corundum has superior pressure resistance and crack resistance, and composite materials manufactured using it as a core possess both high pressure resistance and crack resistance, preventing the collapse of the entire core-shell structure due to core failure, thus ensuring greater rigidity of the thermally conductive system structure.

[0022] Preferably, the cubic boron nitride is obtained by modifying dopamine hydrochloride.

[0023] After the sheet-like hexagonal boron nitride penetrates the thermal conductivity system, cubic boron nitride, as another sheet-like filler, has a relatively large specific surface area, making it prone to common problems between inorganic and organic fillers—namely, low compatibility—when fused with epoxy resin. After modification of cubic boron nitride with dopamine hydrochloride, nanopolydopamine is generated on the surface of the cubic boron nitride. The B and N atoms of the cubic boron nitride alternately form a hexagonal cyclic lattice structure. Furthermore, the specific surface area of ​​the cubic boron nitride nanosheet is very large, making it easy to interact with the benzene ring structure of polydopamine via π-π bond conjugation and van der Waals forces, firmly binding the polydopamine to the surface of the cubic boron nitride. On the other hand, polydopamine molecules and epoxy resin have good compatibility, which helps in fusing cubic boron nitride and epoxy resin to obtain a homogeneous composition.

[0024] Furthermore, when forming a core-shell structure of plate-like corundum and cubic boron nitride, since the compatibility between cubic boron nitride and epoxy resin is more important, it is very important to strengthen the fusion between cubic boron nitride and epoxy resin by modification.

[0025] Preferably, in the composite material of the plate-like corundum and cubic boron nitride, the mass ratio between cubic boron nitride and plate-like corundum is 1:(0.1 - 0.5).

[0026] Preferably, the mass ratio among the composite material of the plate-like corundum and cubic boron nitride, cubic boron arsenide, and sheet-like hexagonal boron nitride is (1:1:2) - (3:3:2).

[0027] Preferably, the high thermal conductivity insulating resin composition further contains 1 - 4 parts of a curing agent.

[0028] The present invention is a method for manufacturing a high thermal conductivity insulating resin composition,

[0029] S1, dispersing cubic boron nitride in absolute ethanol, adding a dopamine hydrochloride solution under stirring conditions, reacting at 50 - 70 °C for 12 - 24 h, filtering after centrifugation to obtain modified cubic boron nitride;

[0030] S2, dispersing the modified cubic boron nitride in water, adding a plate-like corundum dispersion under stirring conditions, filtering after high-speed stirring to obtain a composite material of plate-like corundum and cubic boron nitride;

[0031] S3, heating epoxy resin, the composite material of plate-like corundum and cubic boron nitride, cubic boron arsenide, and hexagonal boron nitride and stirring uniformly, cooling to room temperature, adding a curing agent, stirring uniformly, then pulverizing, suction filtering, and stirring uniformly again to obtain a film solution, that is, a high thermal conductivity insulating resin composition. The present invention further provides a method including these steps.

[0032] The inventors of this invention produce a highly thermally conductive insulating resin composition by modifying cubic boron nitride and then compounding it with plate-like corundum to obtain a preliminary mixed composite material, and then simply mixing this with cubic boron arsenide, sheet-like hexagonal boron nitride, and epoxy resin and heating it. This method is generally less dependent on equipment, can be completed without requiring specific equipment, is low-cost, and is easily disseminated and applied.

[0033] Preferably, stirring is performed under vacuum.

[0034] Vacuum stirring and mixing removes bubbles and gases from the mixture during the mixing process, ensuring a more homogeneous mixture and reducing the impact of pores and bubbles on the composition. At the same time, it improves the fluidity of the mixed components, resulting in a more uniform mix and a more stable and homogeneous composition.

[0035] More preferably, the vacuum level for vacuum stirring is -95 kPa.

[0036] Preferably, in step S3, the pore size of the filter mesh used for suction filtration is 100 μm.

[0037] If the pore size is too small, the resin components cannot be filtered. Therefore, by maintaining a pore size of 100 μm, the desired filtration effect can be achieved, that is, the resin composition obtained by recombining thermally conductive fillers and resin can be smoothly filtered, and powders with particularly large particle sizes (greater than 100 μm) can be sieved off in this process.

[0038] Preferably, in step S3, the heating temperature is 50 to 60°C.

[0039] More preferably, the heating temperature is 55°C.

[0040] The present invention further provides a high thermal conductivity insulating film obtained by thermocuring the above-described high thermal conductivity insulating resin composition or a high thermal conductivity insulating resin composition produced by the above-described method.

[0041] A high thermal conductivity insulating resin composition is uniformly applied to a polytetrafluoroethylene plate and cured in a vacuum drying box to obtain a high thermal conductivity insulating film. The obtained high thermal conductivity insulating film is characterized by a thermal conductivity of 6.30 W / m·K and a thermal diffusivity of 3.42 m·K. 2 It was found that it has a low operating rate ( / s) and good insulation properties, and can meet current production needs.

[0042] Therefore, the present invention has the following beneficial effects.

[0043] (1) The high thermal conductivity insulating resin composition submitted by the present invention constructs a complete thermal conduction network using sheet-like and spherical particulate thermal conductive fillers having different particle sizes, and the designed epoxy resin-thermal conductive filler system exhibits a high thermal conductivity coefficient, high thermal conductivity, and good insulation properties.

[0044] (2) According to the design of the present invention, by pre-compounding plate-like corundum and cubic boron nitride, the interfacial impedance between different thermal conductive materials can be effectively reduced, a three-dimensional dispersed distribution of the thermal conductive system can be achieved, local concentration phenomena such as overlapping of sheets and adhesion between particles can be avoided, and at the same time it is useful for constructing various thermal conductive systems and is advantageous for improving the dispersion and stability of thermal conductive materials, and the introduced plate-like corundum can improve the mechanical properties and heat resistance of the manufactured thermal conductive film.

[0045] (3) According to the design of the present invention, by recombining microscale and nanoscale thermal conductive fillers and combining nanoscale and microscale particles, a multilayer three-dimensional structure can be constructed, and the synergistic effect of the two improves the thermal conductivity of the entire resin composition.

[0046] (4) The present invention provides a method for producing a highly thermally conductive insulating resin composition simply by mixing and heating. This method is generally low in dependence on equipment, low in cost, and easily accessible and applicable.

[0047] (5) The high thermal conductivity insulating film submitted by the present invention is obtained by thermosetting a high thermal conductivity insulating resin composition, has good thermal conductivity and insulating properties, and is widely used in the field of microelectronics integration. [Brief explanation of the drawing]

[0048] [Figure 1] This is a reference diagram showing a cracked high thermal conductivity insulating film.

[0049] [Figure 2] This is a reference diagram of a high thermal conductivity insulating film in a crack-free state. [Modes for carrying out the invention]

[0050] The present invention will be further described below in accordance with specific embodiments. Those skilled in the art will be able to realize the present invention based on these descriptions. Furthermore, the embodiments of the present invention referred to in the following descriptions are usually only a selection of embodiments, not all embodiments. Accordingly, based on the embodiments of the present invention, those skilled in the art should be able to obtain all other embodiments without requiring any creative effort that fall within the scope of the claims of the present invention. [Examples]

[0051] Example 1

[0052] In this example, we selected materials with an average particle size of 2 μm for plate-like corundum, 320 nm for cubic boron nitride, 275 nm for cubic boron arsenide, and 12 μm for sheet-like hexagonal boron nitride.

[0053] S1, cubic boron nitride was dispersed in anhydrous ethanol, and a 2 g / L dopamine hydrochloride solution was added under stirring conditions. The reaction was carried out at 60°C for 12 hours, followed by centrifugation and filtration to obtain modified cubic boron nitride.

[0054] 1 g of modified cubic boron nitride S2 was dispersed in water, and 250 mL of a 2 g / L plate-like corundum dispersion was added under stirring conditions. The mixture was stirred for 6 hours at a rotation speed of 2000 r / min under a vacuum of -95 kPa, and then filtered to obtain a composite material of plate-like corundum and cubic boron nitride. The required amount of composite material was produced by expanding or contracting the above formulation.

[0055] S3, 60g of bisphenol A epoxy resin, 10g of a composite material of plate-like corundum and cubic boron nitride, 10g of cubic boron arsenide, and 20g of hexagonal boron nitride were stirred at 55°C under a vacuum of -95kPa for 1 hour. After cooling to room temperature, 1g of dicyandiamide curing agent was added, the mixture was stirred for 20 minutes, then pulverized, filtered by suction, and stirred for another 15 minutes to obtain a film solution, i.e., a highly thermally conductive insulating resin composition.

[0056] S4. A high thermal conductivity insulating resin composition was uniformly applied to a polytetrafluoroethylene plate and dried in a vacuum drying chamber at 80°C for 6 hours to cure into a thermal conductivity insulating film.

[0057] Example 2

[0058] This embodiment is basically the same as Embodiment 1, with the differences being as follows.

[0059] 1 g of modified cubic boron nitride S2 was dispersed in water, 150 mL of a 2 g / L plate-like corundum dispersion was added under stirring conditions, and the mixture was stirred for 6 hours at a rotation speed of 2000 r / min under a vacuum of -95 kPa. The mixture was then filtered to obtain a composite material of plate-like corundum and cubic boron nitride. The required amount of composite material was produced by expanding or contracting the above formulation.

[0060] Example 3

[0061] This example was basically the same as Example 1, with the differences being as follows: 1 g of modified cubic boron nitride S2 was dispersed in water, 50 mL of a 2 g / L plate-like corundum dispersion was added under stirring conditions, and the mixture was stirred for 6 hours at a rotation speed of 2000 r / min under a vacuum of -95 kPa. The mixture was then filtered to obtain a composite material of plate-like corundum and cubic boron nitride. The required amount of composite material was produced by expanding or contracting the above formulation.

[0062] Example 4

[0063] This embodiment is basically the same as Embodiment 1, with the differences being as follows.

[0064] S3, 60g of bisphenol A epoxy resin, 6g of a composite material of plate-like corundum and cubic boron nitride, 9g of cubic boron arsenide, and 25g of sheet-like hexagonal boron nitride were stirred at 55°C under a vacuum of -95kPa for 1 hour. After cooling to room temperature, 1g of dicyandiamide curing agent was added, the mixture was stirred for 20 minutes, then pulverized, filtered by suction, and stirred for another 15 minutes to obtain a film solution, i.e., a highly thermally conductive insulating resin composition.

[0065] Example 5

[0066] This embodiment is basically the same as Embodiment 1, with the differences being as follows.

[0067] S3, 60g of bisphenol A epoxy resin, 15g of a composite material of plate-like corundum and cubic boron nitride, 15g of cubic boron arsenide, and 10g of sheet-like hexagonal boron nitride were stirred at 55°C under a vacuum of -95kPa for 1 hour. After cooling to room temperature, 1g of dicyandiamide curing agent was added, the mixture was stirred for 20 minutes, then pulverized, filtered by suction, and stirred for another 15 minutes to obtain a film solution, i.e., a highly thermally conductive insulating resin composition.

[0068] Example 6

[0069] This embodiment is basically the same as Embodiment 1, with the differences being as follows.

[0070] S3, 80g of bisphenol A epoxy resin, 5g of a composite material of plate-like corundum and cubic boron nitride, 5g of cubic boron arsenide, and 10g of sheet-like hexagonal boron nitride were stirred at 55°C under a vacuum of -95kPa for 1 hour. After cooling to room temperature, 1g of dicyandiamide curing agent was added, the mixture was stirred for 20 minutes, then pulverized, filtered by suction, and stirred for another 15 minutes to obtain a film solution, i.e., a highly thermally conductive insulating resin composition.

[0071] Example 7

[0072] This embodiment is basically the same as Embodiment 1, with the differences being as follows.

[0073] S3, 70g of bisphenol A epoxy resin, 7.5g of a composite material of plate-like corundum and cubic boron nitride, 7.5g of cubic boron arsenide, and 15g of sheet-like hexagonal boron nitride were stirred at 55°C under a vacuum of -95kPa for 1 hour. After cooling to room temperature, 1g of dicyandiamide curing agent was added, the mixture was stirred for 20 minutes, then pulverized, filtered by suction, and stirred for another 15 minutes to obtain a film solution, i.e., a highly thermally conductive insulating resin composition.

[0074] Example 8

[0075] This embodiment is basically the same as Embodiment 1, with the differences being as follows.

[0076] 50 g of bisphenol A epoxy resin, 12.5 g of a composite material of plate-like corundum and cubic boron nitride, 12.5 g of cubic boron arsenide, and 25 g of sheet-like hexagonal boron nitride were stirred at 55°C under a vacuum of -95 kPa for 1 hour. After cooling to room temperature, 1 g of dicyandiamide curing agent was added, the mixture was stirred for 20 minutes, then pulverized, filtered by suction, and stirred for another 15 minutes to obtain a film solution, i.e., a highly thermally conductive insulating resin composition.

[0077] Example 9

[0078] This embodiment is basically the same as Embodiment 1, with the differences being as follows.

[0079] S3, 40g of bisphenol A epoxy resin, 15g of a composite material of plate-like corundum and cubic boron nitride, 15g of cubic boron arsenide, and 30g of sheet-like hexagonal boron nitride were stirred at 55°C under a vacuum of -95kPa for 1 hour. After cooling to room temperature, 1g of dicyandiamide curing agent was added, the mixture was stirred for 20 minutes, then pulverized, filtered by suction, and stirred for another 15 minutes to obtain a film solution, i.e., a highly thermally conductive insulating resin composition.

[0080] Example 10

[0081] This embodiment is basically the same as Embodiment 1, with the differences being as follows.

[0082] In this example, we selected materials with an average particle size of 1 μm for plate-like corundum, 360 nm for cubic boron nitride, 120 nm for cubic boron arsenide, and 8 μm for sheet-like hexagonal boron nitride.

[0083] Example 11

[0084] This embodiment is basically the same as Embodiment 1, with the differences being as follows.

[0085] In this example, we selected materials with an average particle size of 3 μm for plate-like corundum, 320 nm for cubic boron nitride, 180 nm for cubic boron arsenide, and 15 μm for sheet-like hexagonal boron nitride.

[0086] Comparative Example 1

[0087] This comparative example is basically the same as Example 1, with the following differences.

[0088] S3, 60g of bisphenol A epoxy resin and 40g of a composite material of plate-like corundum and cubic boron nitride were stirred at 55°C under a vacuum of -95kPa for 1 hour. After cooling to room temperature, 1g of dicyandiamide curing agent was added, stirred for 20 minutes, then pulverized, filtered by suction, and stirred for another 15 minutes to obtain a film solution, i.e., a highly thermally conductive insulating resin composition.

[0089] Comparative Example 2

[0090] This comparative example is basically the same as Example 1, with the following differences.

[0091] S3, 60g of bisphenol A epoxy resin, 10g of a composite material of plate-like corundum and cubic boron nitride, and 30g of cubic boron arsenide were stirred at 55°C under a vacuum of -95kPa for 1 hour. After cooling to room temperature, 1g of dicyandiamide curing agent was added, the mixture was stirred for 20 minutes, then ground, filtered by suction, and stirred for another 15 minutes to obtain a film solution, i.e., a highly thermally conductive insulating resin composition.

[0092] Comparative Example 3

[0093] This comparative example is basically the same as Example 1, with the following differences.

[0094] S3, 60g of bisphenol A epoxy resin, 10g of a composite material of plate-like corundum and cubic boron nitride, and 30g of sheet-like hexagonal boron nitride were stirred at 55°C under a vacuum of -95kPa for 1 hour. After cooling to room temperature, 1g of dicyandiamide curing agent was added, the mixture was stirred for 20 minutes, then pulverized, filtered by suction, and stirred for another 15 minutes to obtain a film solution, i.e., a highly thermally conductive insulating resin composition.

[0095] Comparative Example 4

[0096] This comparative example is basically the same as Example 1, with the following differences.

[0097] After removing the S2 composite, S3, 60g of bisphenol A epoxy resin, 6.7g of plate-like corundum, 3.3g of cubic boron nitride, 10g of cubic boron arsenide, and 20g of sheet-like hexagonal boron nitride were stirred at 55°C under a vacuum of -95kPa for 1 hour. After cooling to room temperature, 1g of dicyandiamide curing agent was added, the mixture was stirred for 20 minutes, then pulverized, filtered by suction, and stirred for another 15 minutes to obtain a film solution, i.e., a highly thermally conductive insulating resin composition.

[0098] Comparative Example 5

[0099] This comparative example was basically the same as Example 1, with the following differences: The modification step of S1 was removed, and the compounding was performed directly.

[0100] <Performance Test>

[0101] 1. The effect of different ratios of cubic boron nitride and plate-like corundum.

[0102] To investigate the effect of the addition ratio of plate-like corundum nanocrystals on the thermal stability and dielectric strength of high thermal conductivity insulating films, the high thermal conductivity insulating films manufactured in Examples 1-3 were used in a hot-press experiment on a double-sided copper-coated plate (the upper and lower copper foils were 0.3 mm and 0.8 mm oxygen-free copper, respectively, and the hot-press time was standardized to 1 hour). The copper-coated plate after hot-pressing was scanned with an ultrasonic scanner to check for cracks in the central high thermal conductivity insulating film, and the hot-press results were as follows. Table 1 Hot pressing results for Example 1 [Table 1] Table 2 Hot pressing results for Example 2 [Table 2] Table 3 Hot Press Results of Example 3 [Table 3]

[0103] As can be seen from the results in Tables 1-3, comparing the effects of film cracking in Figures 1-2, the entire film without cracks is smooth, flat, and gap-free, whereas under high temperature and pressure, serious cracking is more likely to occur in the film, affecting its service life. When the mass ratio of cubic boron nitride to plate-like corundum is 1:0.5, the high thermal conductivity insulating film exhibits superior thermal stability and pressure resistance, guaranteeing that the film will not crack at 190°C and 2.5 MPa.

[0104] 2. Effects of different formulations of thermally conductive fillers

[0105] After determining the optimal blend of cubic boron nitride and plate-like corundum, the effect of the thermally conductive filler blend on high thermal conductivity insulating films was investigated based on this. Thermal conductivity, thermal diffusivity, and insulating properties were tested for the films obtained in Examples 1, 4, and 5, and the results are shown in Table 4.

[0106] Table 4: Test results of films with different thermally conductive filler formulations [Table 4]

[0107] As can be seen from the data in the table, the thermal conductivity and thermal diffusivity of the film gradually decreased as the total amount of plate-like corundum and cubic boron nitride in the system increased. This is related to the fact that plate-like corundum itself does not have as good thermal conductivity as boron nitride, and its addition is mainly to improve the mechanical properties and heat resistance of the film.

[0108] 3. The effect of different ratios of filler and epoxy resin

[0109] After determining the optimal formulation of the thermally conductive filler, the effects of different ratios of filler and resin on high thermal conductivity insulating films were investigated based on this. Thermal conductivity, thermal diffusivity, and insulating properties were tested for the films obtained in Examples 1, 6-9, and the results are shown in Table 5.

[0110] Table 5 Test results of films with different filler ratios [Table 5]

[0111] As can be seen from the data in the table, each aspect of the film's performance improved effectively with increasing filler usage. When the ratio of filler to resin usage exceeded 2:3, each aspect of the film's performance could reach a high level, and the film's performance continued to improve with a continuous increase in filler usage.

[0112] 4. Impact of heat conduction network construction

[0113] The films obtained in Example 1 and Comparative Examples 1-5 were tested for thermal conductivity, thermal diffusivity, and insulation properties, and the results are shown in Table 6.

[0114] Table 6 Test results of films in different thermal conduction networks [Table 6]

[0115] As can be seen from the data in the table, Comparative Examples 1-3 lacked cubic boron arsenide and / or sheet-like hexagonal boron nitride. The absence of sheet-like hexagonal boron nitride meant the film lacked the most important thermally conductive support material, resulting in a significant decrease in its performance, particularly its thermal conductivity.

[0116] As can be seen by comparing the data of Example 1 and Comparative Example 4, when plate-like corundum and cubic boron nitride were added directly to bisphenol A epoxy resin without prior compounding and mixed, the performance deteriorated, and the thermal conductivity and thermal diffusivity decreased compared to when they were added in a pre-mixed state. This is because, in the mixing process of thermally conductive fillers, overlapping of sheet-like structures and adhesion between particles cause localized concentration, reducing the dispersibility of the thermally conductive fillers. As a result, the distribution of fillers at each position becomes uneven, and adhesion occurs, preventing the optimal performance of different fillers from being realized. This prevents optimal synergistic effects between fillers with different forms and particle sizes, leading to a decrease in performance.

[0117] In summary, it was found that pre-mixing of plate-like corundum and cubic boron nitride, and intermixing of different fillers with different particle sizes, are necessary for the integrity of the thermal conduction network. The high thermal conductivity insulating film produced by this method has a high degree of thermal conduction network integrity and can simultaneously possess high thermal conductivity, high insulation, and high stability.

Claims

1. A highly thermally conductive insulating resin composition, The mixture contains 40 to 80 parts by weight of epoxy resin and 20 to 60 parts by weight of thermally conductive filler, where the thermally conductive filler includes a composite material of plate-like corundum and cubic boron nitride, cubic boron arsenide, and sheet-like hexagonal boron nitride. A highly thermally conductive insulating resin composition characterized by the following:

2. The average particle size of the plate-like corundum is 1 to 3 μm, the average particle size of the cubic boron nitride is 100 to 400 nm, the average particle size of the cubic boron arsenide is 100 to 300 nm, and the average particle size of the sheet-like hexagonal boron nitride is 5 to 15 μm. The high thermal conductivity insulating resin composition according to feature 1.

3. The composite material of plate-like corundum and cubic boron nitride is obtained by compounding plate-like corundum having a relatively large grain size as the core and cubic boron nitride having a relatively small grain size as the shell. The high thermal conductivity insulating resin composition according to feature 2.

4. The cubic boron nitride mentioned above is obtained by modifying dopamine hydrochloride. A high thermal conductivity insulating resin composition according to claim 1 or 3, characterized in that it is a high thermal conductivity insulating resin composition.

5. In the composite material of plate-like corundum and cubic boron nitride, the mass ratio between cubic boron nitride and plate-like corundum is 1:(0.1 to 0.5). The high thermal conductivity insulating resin composition according to feature 1.

6. The mass ratio between the composite material of plate-like corundum and cubic boron nitride, cubic boron arsenide, and sheet-like hexagonal boron nitride is (1:1:2) to (3:3:2). The high thermal conductivity insulating resin composition according to claim 1, 2, 3, or 5, characterized in that it is as described above.

7. The aforementioned high thermal conductivity insulating resin composition further comprises 1 to 4 parts of a curing agent. The high thermal conductivity insulating resin composition according to feature 6.

8. A method for producing a high thermal conductivity insulating resin composition according to any one of claims 1 to 7, Step S1: Disperse cubic boron nitride in anhydrous ethanol, add dopamine hydrochloride solution under stirring conditions, react at 50-70°C for 12-24 hours, centrifuge, and filter to obtain modified cubic boron nitride. Step S2: Disperse modified cubic boron nitride in water, add plate-like corundum dispersion under stirring conditions, stir at high speed, and then filter to obtain a composite material of plate-like corundum and cubic boron nitride. The process includes the steps of heating epoxy resin, a composite material of plate-like corundum and cubic boron nitride, cubic boron arsenide, and sheet-like hexagonal boron nitride, stirring uniformly, cooling to room temperature, adding a curing agent, stirring uniformly, grinding, suction filtering, stirring uniformly again to obtain a film solution, i.e., a highly thermally conductive insulating resin composition. A method characterized by the following:

9. In step S3, the pore size of the filter mesh used for suction filtration is 100 μm. The method according to feature 8.

10. A highly thermally conductive insulating film, A high thermal conductivity insulating resin composition obtained by thermocuring a high thermal conductivity insulating resin composition produced by any one of claims 1 to 7 or by the method described in any one of claims 8 to 9. A highly thermally conductive insulating film characterized by the following features.

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